Victron MODBUS with Home Assistant - strange register behaviour

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xtopher asked Aug 24, '22

Victron MODBUS with Home Assistant - strange register behaviour

Hi all,

Has anyone seen an issue with register 789 - 'PV power' on the MODBUS? I've seen that it reports properly a lot of the time but I've just seen it go a bit haywire and report negative completely unrealistic numbers, then after an amount of time goes back to normal? It made my HA dashboard go nuts as it couldn't balance the readings so was reading zero for PV Power when it was actually it was at multiple KW output

Here is an example in HA - number has gone negative:

And history graph, see it is often giving negative reading?

Actually managed to get them together using remote console:

Any ideas why its going negative?

Here's the config:

This is with a MTTP RS 450/100, Multiplus II and Cerbo GX (f/w: 2.89)

Modbus TCP

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xtopher commented · Aug 24, 2022 at 11:36 AM

Digging a bit more it appears it can't ever report over 3.2kW? If it goes over that then I get the crazy negative numbers? I'd not been using this register until recently as I'd just been using the 'yeild today' in HA to get it to display on the historical energy graph. Now I'm trying to output near real time numbers I've started to use this 789 register.

This is the past week:

Its almost as if it goes over 3.2kW, its then reporting negative the same value rather than the ~5+kW that is actually being generated?

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Modifications Space

Node Red Space

Answer 1 · 2022-08-24T11:51:10Z

xtopher answered · Aug 24, 2022 at 11:51 AM

OK think I've been using the wrong register, I should be using the highlighted one below, that is giving the right reading

Any ideas why the details for Tracker 0 and Tracker 1 appear to be the same? Should they have different addresses? Seems like a typo? I don't need the individual tracker details but could be handy.

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xtopher commented · Aug 25, 2022 at 01:47 PM

@Guy Stewart (Victron Community Manager)@mvader (Victron Energy) - looks like there is a typo in the CCGX Modbus register list spreadsheet (2.80)

As above comment, 'PV power for tracker 0' should be Address 3724 (not 3725). **Note I've added column A above to track by unit ID - that is not in the spreadsheet.

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mvader (Victron Energy) ♦♦ xtopher commented · Aug 25, 2022 at 03:02 PM

Hi @Xtopher thank you; noted. We'll fix that. Matthijs

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